Ted Kaczynski is flanked by federal agents as he is led from the federal courthouse in Helena, Mont., on April 4, 1996. Kaczynski is now serving a life sentence in prison for the bombings.
John Youngbear/Associated Press
Oklahoma City Bombing: The Albert P. Murrah Federal Building shows the devastation caused by a fuel and fertilizer truck bomb on April 19, 1995. The blast killed 168 people and injured more than 500.
Bob Daemmrich/AFP/Getty Images